1975 Johnson 70 hp .......... new information

[cvlngineer]

I took the boat out yesterday and it did better, but there was still some bogging.<br /><br />In forward gear...<br /><br />The motor ran fine from idle up to 1600 rpm. Slowly adding more throttle bogged the engine, and it died at 1650-1700 rpm. If I gave it throttle quickly, most of the time it would bog at 1650-1700 momentarily and then jump up to 2000 rpm and would run fine from there on up to WOT. After making the jump up to 2000 rpm, I could back the throttle down to 1700-1800 rpm with no trouble accelerating afterward. There seems to be a dead spot right around 1650-1750 rpm. <br /><br />Any ideas?<br /><br />cvlngineer

 

[petryshyn]

Re: 1975 Johnson 70 hp .......... new information

I'll presume the carbs have been gone through...<br /><br />>Try maintaining a hard primer bulb by continually squeezing it. This may indicate fuel supply issue.<br /><br />>Try applying the choke when bogging, does it help? <br /><br />>try manually changing the timing while bogging. If it improves, reset link/sink<br /><br />>try richening the idle mixture 1/4 turn at a time. This can help a "starvation transfer" from idle to WOT.

 

[cvlngineer]

Re: 1975 Johnson 70 hp .......... new information

schematic,<br /><br />I have tried squeezing the bulb, but that doesn't help. <br /><br />I will give choking it a try, but there are no adjustment needles on these carbs.<br /><br />Thanks,<br />cvlngineer